Binding of Herbicides by Water‐soluble Organic Materials from Soil

Abstract

Abstract The gel filtration method of Hummel and Dreyer (1962) has been used for the study of binding of herbicides by water‐soluble organic substances extracted from soil with distilled water. Evidence is offered for the binding of bromacil (5‐bromo‐3‐sec‐butyl‐6‐methyluracil), diuron [3‐(3,4‐dichlorophenyl)‐1,1,dimethylurea], chlorotoluron [3‐(3‐chloro‐4‐methylphenyl)‐1,1‐dimethylurea], simazine (2‐chloro‐4,6‐bis‐ethylamino‐s‐triazine), glyphosate [N‐(phosphonomethyl) glycine], and diquat (1,1‐ethylene‐2,2‐bipyridylium ion) by water soluble soil organic materials (WSSOM). Infrared and gel filtration data showed that the WSSOM consist of compounds with molecular masses in the range of 700 to 5000 daltons and resemble very closely the fulvic acids present in soil and surface waters. The amount of herbicide bound by WSSOM was determined from the elution diagram of the herbicide‐WSSOM complex. The results of this study point to the significance of WSSOM in relation to the fate and behavior of pesticides and pollutants in soil and water. The binding of these chemicals by WSSOM may figure important in the assessment of their mobility and transport in the environment.